Often, medications are given by mouth or by intramuscular, intravascular, or intravenous injection. With larger doses or with a continuing dose, intravascular or intravenous (IV) application may be used. IV's are problematic because they often lead to hematomas on or other irritation to the patient and cause vessels to collapse. When used over an extended period of time, they can be traumatic and unreliable for the patient.
Single lumen catheters have been used, with or without surgical implantation, to convey fluids.
During the last decade, it became popular to use surgically implanted catheters to allow more reliable and dependable monitoring of conditions and application of medications. Single-lumen and dual-lumen tubes have been used. Usually the dual-lumen tubes have a cylindrical outside periphery and an internal wall to separate the lumen into two portions. These catheters are more rigid than desirable and have pressure limitations which limit the uses of the catheter. Control of the separate channel sizes can be difficult. Figure-8, dual-lumen catheters have side-by-side tubes so that each catheter resembles a double-barrel shotgun of the over-and-under variety. The tubes are connected so that grooves appear on each side of the catheter. When implanted into vessels, the first figure-8, dual-lumen catheter leaked vessel fluids and allowed bacteria to enter the patient along the grooves of the catheter tubes. The blood leakage problem was stopped by filling in a portion to the figure-8, dual-lumen catheter at the point where the catheter passed through the vessel. When used, the patients were still subject to increased incidence of infection.